The carpet in the BMW when I purchased it was faded and a bit rough. I also had some rust repairs to do so it got torn out. For a replacement, I considered the nice offerings from Esty but figured I could do something acceptable for much less.
The carpet I chose is a high wear, office type carpet from Lowe’s. The original pieces could potentially have been used to create the replacements but they were in poor shape. Instead, I used a large roll of plotter paper to create some oversized templates. These were then taped into the car and trimmed until they would fit with a few inches overlap and lay mostly flat. If you can get paper to lay flat, carpet is easy!
Finally, I cut the pieces out and laid them in the car for final fitting and trimming. Prior to final glueing, I put down some Peel & Seal for sound deadening. I may go back and add more thermal insulation as the turbo and exhaust are heating up the cabin.
The final result was very satisfactory for <$100 including carpet, glue and the Peel & Seal.